     :ImplementationName
     :ImplementationVersion
     :DowntimeEnd
-    :TrustedCA))
-
-(def-class :Activity)
+    :TrustedCA)
+  (extends :Entity))
+
+(def-class :Activity
+  (extends :Entity))
 
 (def-class :Policy
   (with-attributes
     :Rule
-    :Scheme))
-
-(def-class :AccessPolicy)
-
-(def-class :MappingPolicy)
-
-
-(def-class :UserDomain
-  (with-attributes
-    :Member
-    :UserManager
-    :Level))
+    :Scheme)
+  (extends :Entity))
+
+(def-class :AccessPolicy
+  (extends :Policy))
+
+(def-class :MappingPolicy
+  (extends :Policy))
+
 
 (association ""
   "role1" :Extension 1 1

(def-class :Share
  (with-attributes
    :Description))

(def-class :Service
  (with-attributes

    :QualityLevel
    :Capability
    :Type
    :Complexity)
  (extends :Entity))

(def-class :Location
  (with-attributes
